With the advancement of automation technology, in industrial equipment, in addition to liquid column pressure gauges and elastic pressure gauges, more and more pressure transmitters and sensors that can convert pressure into electrical signals are currently used. What are the working principles and usage methods of common pressure sensors?

Working principle of pressure sensor

Piezoresistive force sensor:
Resistance strain gauges are one of the main components of piezoresistive strain sensors. The working principle of metal resistance strain gauges is to adsorb on the substrate material, and the strain resistance changes with mechanical deformation, commonly known as the resistance strain effect.

Diffuse silicon pressure sensor:
The working principle of diffused silicon pressure sensors is also based on the piezoresistive effect. Using the principle of piezoresistive effect, the pressure of the measured medium directly acts on the diaphragm of the sensor(Stainless steel or ceramic), the diaphragm produces a micro displacement proportional to the medium pressure, causing a change in the resistance value of the sensor. This change is detected using electronic circuits and converted into a standard measurement signal corresponding to this pressure.

Sapphire pressure sensor:
Utilizing the principle of strain resistance, using silicon-Sapphire, as a semiconductor sensitive component, hasMeasurement characteristics. Therefore, semiconductor sensitive components made of silicon sapphire are insensitive to temperature changes and have good working characteristics even under high temperature conditions; Sapphire has good radiation resistance propertiesIn addition, silicon sapphire semiconductor sensitive components have no p-n drift.

Piezoelectric pressure sensor：
The piezoelectric effect is the main working principle of piezoelectric sensors. Piezoelectric sensors cannot be used for static measurements because the charge generated by external forces is only preserved when the circuit has an infinite input impedance. The actual situation is not like this, so this determines that piezoelectric sensors can only measure dynamic stress.

Ceramic pressure sensor：
Ceramic pressure sensors are based on the piezoresistive effect, where pressure directly acts on the front surface of the ceramic diaphragm, causing slight deformation of the diaphragm. Thick film resistors are printed on the back of the ceramic diaphragm and connected to form a Wheatstone bridge. Due to the piezoresistive effect of the varistor, the bridge generates a highly linear voltage signal that is proportional to the pressure and proportional to the excitation voltage. The standard signal is calibrated according to the different pressure ranges2.0/3.0/3.3mv/v, etc., can be compatible with strain gauges.

Instructions for using pressure sensors

（1）Prevent the transmitter from coming into contact with corrosive or overheated media;
（2）Prevent sediment from settling inside the conduit;
（3）When measuring liquid pressure, the pressure tap should be opened on the side of the process pipeline to avoid sedimentation and slag accumulation;
（4）When measuring gas pressure, the pressure tap should be opened at the top of the process pipeline, and the transmitter should also be installed at the top of the process pipeline to facilitate the injection of accumulated liquid into the process pipeline;
（5）The pressure conduit should be installed in a location with minimal temperature fluctuations.